Hi Rudy, it looks like you're currently trying to sweep the shape kind of "in place" directly.

It is possible to do that, but somewhat more difficult - here I will show you a different approach of combining more simple shapes, I'm not sure if it will be exactly what you need but it will make for a clean shell though.

To start with, I drew a profile curve in the front view:



I made sure there that the 2 ending points on each side are horizontal or vertical with one another to make sure the next step will be smoothly rounded.

Then select that profile, and run Construct / Revolve, and pick this as the revolve axis:



That creates this base form:



Now switch to the Top view, and draw a circle:



Select the base form, and run Construct / Boolean / Difference, and select the circle as the cutting object. That will leave you with this shape:



Now it is probably a good idea to shell it first, go to the under-side of the object and select that bottom face, then you can shell it:



After that you can select this edge:



And fillet:





- Michael

Otherwise to build it more directly in place, you'll want to split those curves into 2 pieces to use as rails for a 2-rail sweep like Pilou shows. Shelling may have some difficulty processing a sweep like that, you may have to create an interior surface manually by doing another sweep for the inside part instead of using Shell if you go that method and shell has problems with it.

- Michael

Hi Rudy,

Here's a basic version I did based on your supplied curves.
It still needs to be shelled or hollowed out.

I ended up splitting your crescent moon shape & using them as a 2 Rail Sweep.
I also tidied up some of the points in those curve towards the very ends.

Hope it helps, Colin

Edit: I just quickly did a hollowed version.

Hej Guys,
thank you so much!
I have all these great ways to play around...

Wish everyone success.

Best,
Rudy